President-elect Donald Trump’s spokesman Jason Miller suggests Trump’s post on Twitter blasting Boeing for a $4 billion contract to build a new Air Force One speaks to Trump’s focus on keeping government spending down.

“When you look at the cost of the two new Air Force Ones plus the research and development — overall program cost — it’s a pretty big number,” Miller stated when questioned about the President-elect’s tweet earlier on Tuesday. “I think this really speaks to the President-elect’s focus on keeping costs down across the board with regard to government spending.”

“I think people are really frustrated with some of the big price tags that are coming out from programs even in addition to this one, so we’re going to look for areas where we can keep costs down and look for ways where we can save money,” Miller added.

The question about Boeing comes after Trump tweeted early on Tuesday morning, “Boeing is building a brand new 747 Air Force One for future presidents, but costs are out of control, more than $4 billion. Cancel order!”

He later explained his tweet to reporters.

“Well the plane is totally out of control, going to be over four billion dollars for the Air Force One program, and I think it’s ridiculous,” Trump stated. “I think Boeing is doing a little bit of a number. We want Boeing to make a lot of money but not that much money.”

Miller said the exact details that Trump will push forward will come after he is sworn into office, but ultimately the tweet about Boeing represents Trump looking for ways to save tax payer money.

We are currently under contract for $170 million to help determine the capabilities of these complex military aircraft that serve the unique requirements of the President of the United States. We look forward to working with the U.S. Air Force on subsequent phases of the program allowing us to deliver the best planes for the President at the best value for the American taxpayer.